Systems and methods for controlling the internal environment of an enclosure

ABSTRACT

In accordance with aspects of the present disclosure, a system and method of controlling the internal environment of an enclosure is provided. The system and method includes either increasing or decreasing the temperature of the enclosure to a predetermined target under normal operating conditions. The system and method further includes selectively engaging a trip condition in response to an overheat limit temperature. During the trip condition, the power relays for the fixture will be opened until the enclosure internal temperature has dropped. The system and method uses various sensors to control environmental conditions and may be controlled remotely.

BACKGROUND

Video projectors, conventional lighting units, moving lights, laserprojectors, and other luminaires (collectively “lighting fixture” or“fixture”) include components and materials which are sensitive tovariations in environment, including: temperature, humidity, moisture,precipitation, electrical discharge, impact, and vibration. Lightingfixtures generally include rudimentary means of controlling excessivelyhigh temperature by using one or more cooling fans, where the fan dutycycles are directly related to measured temperature within the lightingfixture and normally emit noise that can be perceived by people andrecording equipment in proximity with the unit. Typically, lightingfixtures do not have the means to directly control humidity andmoisture, which can increase the risk of corrosion and other types ofdamage to the internal components. The danger of corrosion directlylimits the locations in which they may be utilized, such as outdoors,humid environments, or anywhere near water.

Lighting fixtures are widely used in locations where quiet operation isan advantage, such as lecture halls, auditoriums, houses of worship, andmovie sets. Some applications require dismantling the lighting fixtureand moving some component to other areas where the noise is notbothersome. This limits the durability and efficiency of the lightingfixture and is often not practical.

A separate enclosure can be used in conjunction with the lightingfixture to protect against temperature, humidity, precipitation, andother environmental stress. In addition, the enclosure can reduce thenoise created by the lighting fixture. Finally, the enclosure cancontrol the internal temperature in order to maintain ideal operatingconditions for the projector unit, regardless of the surroundingenvironment.

Enclosure environment controls are known in general, what is needed is asystem that is configured to respond to parameters other than by directreaction to internal temperature. This system needs to considerhumidity, temperature, power usage, user-defined limits, and duty cycleswhen determining a control strategy.

SUMMARY

In accordance with aspects of the present disclosure, a system andmethod of controlling the internal environment of an enclosure isprovided. The system and method can control the environment byincreasing or decreasing the temperature of the enclosure to apredetermined target under normal operating conditions utilizing atleast one fan and at least one heater based upon criteria mostlycomprising temperature and humidity measurements. The system and methodfurther includes selectively engaging a trip condition in response to anoverheat limit temperature. During the trip condition, the power relaysfor the enclosure will be opened until the enclosure internaltemperature has dropped. The system and method may also be controlled bya remote data communication. The system and method can further includeat least one fan for stirring the air within the enclosure. The systemand method further comprises the duty cycle calculation for determiningthe duration and interval of each heater and fan operation.

One embodiment of the system for controlling the enclosure environmentcomprises a temperature measurement and a relative humidity measurementand utilizes user-configurable temperature and humidity limits toactivate a heater to adjust relative humidity and a fan to adjusttemperature when factoring in the heater duty cycle and fan duty cycle.This system may also limit power to the enclosed lighting fixture inorder to reduce internal enclosure temperature. One preferred powerlimitation length of time is at least four minutes.

The embodiment may further comprise a user-configurable maximum powerdraw of the system and the contained lighting fixture where the heaterduty cycle is adjustable based upon total system power usage. The fanduty cycle may also be adjusted in order to reduce overall orintermittent noise.

This embodiment may further comprise at least one additional fan forstirring the air within the enclosure designed to increase thetemperature monitoring accuracy.

Another embodiment of a method of controlling the internal environmentof an enclosure comprises a plurality of sensors to determine a fan dutycycle to operate a fan and a heater duty cycle to operate a heater. Thisembodiment may further comprise determining either or both of the dutycycles based upon the enclosure internal temperature measurement and theuser-configurable upper temperature limit. Alternatively, the system maydetermine either or both duty cycles based upon a calculated idealtemperature and relative humidity threshold. Finally, the system maydetermine either or both duty cycles based upon both the enclosureinternal temperature measurement and the relative humidity measurement.The plurality of sensors are comprised of at least one temperaturesensor, at least one relative humidity sensor, at lease one voltagesensor, and at least one amperage sensor. In this embodiment, either orboth duty cycles may factor in data from the voltage sensor and theamperage sensor.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features ofthe claimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of disclosedsubject matter will become more readily appreciated as the same becomebetter understood by reference to the following detailed description,when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram illustrating an embodiment of a method ofcontrolling an internal enclosure environment according to variousaspects of the present disclosure;

FIG. 2 is a block diagram illustrating an embodiment of an enclosure andan environmental control system according to various aspects of thepresent disclosure;

FIG. 3 is a graph that illustrates relative humidity values with respectto internal air volume temperature values as may be used by variousembodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings, where like numerals reference like elements, is intended onlyas a description of various embodiments of the disclosed subject matterand is not intended to represent the only embodiments. Each embodimentdescribed in this disclosure is provided merely as an example orillustration and should not be construed as preferred or advantageousover other embodiments. The illustrative examples provided herein arenot intended to be exhaustive or to limit the disclosure to the preciseforms disclosed. Similarly, any steps described herein may beinterchangeable with other steps, or combinations of steps, in order toachieve the same or substantially similar result.

Although the present disclosure is described hereinafter with referenceto video projector units, it will be appreciated that aspects of thepresent disclosure have wide application, and therefore, may be suitablefor use with many types of electronic units and/or illuminating device,such as conventional lighting fixtures, intelligent lighting fixtures,laser projectors, video cameras, audio equipment, computers, otherluminaires, etc. Any applicable unit and/or device shall be referred toas “lighting fixture” in this disclosure. Accordingly, the followingdescriptions and illustrations herein should be considered illustrativein nature, and thus, not limiting the scope of the claimed subjectmatter.

Prior to discussing the details of various aspects of the presentdisclosure, it should be understood that several sections of thefollowing description are presented largely in terms of logic andoperations that may be performed by conventional electronic components.These electronic components, which may be grouped in a single locationor distributed over a wide area, generally include processors, memory,storage devices, display devices, input devices, etc. It will beappreciated by one skilled in the art that the logic described hereinmay be implemented in a variety of hardware, software, and combinationhardware/software configurations, including but not limited to, analogcircuitry, digital circuitry, processing units, and the like. Incircumstances where the components are distributed, the components maybe accessible to each other via communication links.

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of exemplary embodiments ofthe present disclosure. It will be apparent to one skilled in the art,however, that many embodiments of the present disclosure may bepracticed without some or all of the specific details. In someinstances, well-known process steps have not been described in detail inorder not to obscure unnecessarily various aspects of the presentdisclosure. Furthermore, it will be appreciated the embodiments of thepresent disclosure may employ any of the features described herein.

FIG. 1 is a block diagram illustrating an embodiment of a method ofcontrolling an internal enclosure environment according to variousaspects of the present disclosure. The present disclosure is includedwithin an enclosure 100 designed to enclose a lighting fixture 128. Thelighting fixture 128 includes many features known to one of ordinaryskill in the art as being included, such as a lamp, a lens, a body, asystem controller, and so on.

The illustrated enclosure 100 includes various sensors, including atemperature sensor 102, a relative humidity sensor 104, an amperagemeter 106, and a voltage meter 108. The temperature sensor 102determines the temperature of the volume of air within the enclosure100. The relative humidity sensor 104 determines the relative humidityof the volume of air within the enclosure 100. The amperage meter 106determines the electrical current draw of the lighting fixture 128. Thevoltage meter 108 determines the electrical voltage of the lightingfixture 128. The various sensors, described above, provide real-timeinputs to the various sub-systems of the enclosure 100. The inputs arerequired to monitor and maintain the internal environment of theenclosure 100 at the desired levels.

The temperature sensor 102 provides the temperature of the volume of airwithin the enclosure 100 to a variety of sub-systems. It provides datato the minimum target temperature sub-system (MTT) 110. The relativehumidity sensor 104 provides the relative humidity of the volume of airwithin the enclosure 100 to the MTT 110. The MTT 110 uses the data fromthe sensors to determine the minimum, or ideal, temperature that will berequired to keep the relative humidity of the internal environment ofthe enclosure 100 within the requirement of the maximum allowed relativehumidity, which is user defined, and the minimum enclosure internaltemperature. The temperature sensor 102 also provides data to the fantemperature control sub-system (FTC) 112. The FTC 112 is a system tocool the enclosure 100 proportionately when the enclosed temperaturerises above the cooling threshold. The temperature sensor 102 alsoprovides data to the heater temperature control sub-system (HTC) 114.The HTC 114 is a system to maintain a minimum temperature as determinedby the ideal temperature.

The FTC 112 determines a required fan duty factor and provides thefactor as an output to the fan duty cycle controller (FDC) 118. The FDC118 is a system to switch one or more fans on periodically according tothe required duty cycle relayed by the FTC 112. The FDC 118 output sendselectrical power to the fan switch 124. In some circumstance, such asuse in noise sensitive areas such as theatrical or video production use,the FTC 112 may also be operated in a “Hush” mode designed to reducenoise levels by reducing FDC 118 interval and duration. The FTC 112 alsohas an output to the lighting fixture power relay 122. The FTC 112 canopen the power relay 122 to interrupt power to the lighting fixture 128when the trip condition is engaged. In some embodiments, at least onefan is activated in order to maintain the temperature of the volume ofair within the enclosure 100 below the upper temperature: a user-definedvalue. This is especially critical when the lighting fixture 128 isdrawing substantial power and generating heat. This may be required whenthe temperature of the volume of air within the enclosure 100 exceedsthe configurable Limit_Temp 310 where continued usage may cause damageto the lighting fixture or reduce useful lamp life.

The HTC 114 determines a required heater duty factor and provides thefactor as an output to the heater duty cycle controller (HDC) 120. TheHDC 120 is a system to switch one or more heaters on periodicallyaccording to the required duty cycle relayed by the HTC 114. The HDC 120output sends electrical power to the heater switch 126. In someembodiments, at least one heater is activated in order to maintain thetemperature of the volume of air within the enclosure 100 above theminimum temperature determined by the MTT 110. This is especiallycritical when the lighting fixture 128 is not drawing power and theexternal air temperature is cooler than the minimum temperaturedetermined by the MTT 110. This prevents a variety of issues to thefixture caused by condensation and temperature changes such as circuitryoxidation, metal oxidation, environmental damage to optics, and changescaused by variability in material expansion and contraction.

The amperage meter 106 determines the electrical current draw of thelighting fixture 128. The amperage meter 106 provides data to the loadpower calculation sub-system (PWR) 116. The purpose of the PWR 116 is toprovide a real-time calculation of the electrical power drawn by thelighting fixture 128.

The voltage meter 108 determines the electrical voltage of the lightingfixture 128. The voltage meter 108 provides data to the PWR 116 toenable the real-time calculation of the electrical power drawn by thelighting fixture 128. The PWR 116 provides data to the FTC 112 to enablethe FTC 112 to run the FDC 118 at a duty cycle proportional to the powerdrawn by the enclosed lighting fixture 128. This is necessary to avoidsharp temperature spikes in the enclosure 100 during high power drawevents. The PWR 116 provides data to the HTC 114 to run the HDC 120 at aduty cycle inversely proportional to the power drawn by the enclosedlighting fixture 128. This is necessary to avoid excessive power draw bythe enclosure 100 and maintain system stability. The PWR 116 alsoprovides a signal directly to the HDC 120 to inhibit the heateroperation should the lighting fixture power draw approach the maximumsystem power rating.

A lighting fixture may be in a deactivated state, a standby state, or anactive state where the lamp is active. The PWR 116 is able to determinethe state of the fixture based upon data from the amperage meter 106 andthe voltage meter 108. In a deactivated state, the fixture draws nopower. In a standby state, the lighting fixture draws power in the rangeof 0.2 amperes to 2 amperes. Amperage draw exceeding a user-configurablepower draw within this range correlates with an active state. The PWR116 maintains a count of the hours in which the enclosed fixture is inan active state. Lighting fixture lamps require replacing after a numberof hours and failing to do so reduces lighting fixture intensity and maycause a lamp failure with prolonged usage beyond the useful life. A lampfailure can cause damage to the various lighting fixture components. Theenclosure 100 provides lamp hour data without requiring access to thelighting fixture 128. The lamp hour data is also accessible via remotedata communication 212 to the user 214.

One of ordinary skill in the art will recognize that the enclosure 100may include components in a different configuration than that depictedin FIG. 1. For example, in some embodiments, the FDC 118 may controladditional fans which are configured to mix the air inside the enclosure100, as opposed to exchanging air with the exterior environment. Inanother embodiment, components of the system may be located outside ofthe enclosure 100. Each of the examples described is exemplary only, andone of ordinary skill in the art will recognize that otherconfigurations are possible without departing from the scope of thepresent disclosure.

FIG. 2 is a block diagram illustrating an embodiment of an enclosure andan environmental control system according to various aspects of thepresent disclosure. The present disclosure is included within anenclosure 200 designed to surround a lighting fixture 226. The enclosure200 includes various sensors, the sensors described previously,including a temperature sensor 202, a relative humidity sensor 204, anamperage meter 206, and a voltage meter 208.

In one embodiment, the system controller 210 receives the signals fromeach sensor. The system controller 210 includes the sub-systems asdescribed previously. In addition, the system controller 210 sends andreceives information from a remote data communication source 212. Theuser 214 can utilize the remote data communication 212 to send andreceive data from the system controller 210, such as power signals,manual override commands, sensor readings, sub-system calculationoutput, relay status, lighting fixture data, software information, andso on. In one embodiment, the remote data communication protocol isremote device management (RDM), USITT DMX512-A, and/or ArtNet.

The system controller 210 sends fan duty cycle data to the FDC 216. TheFDC enables at least one fan 222 to exchange air with external ambientair in order to cool the internal air volume temperature. The FDC 216may also enable at least one mixing fan 224 to stir the air within theenclosure 200 to avoid temperature gradients. In addition, the mixingfan 224 increases effectiveness of the heater(s) 228 and fan(s) 222. Thesystem controller 210 sends a signal to the power relay 218 to enablepower to the lighting fixture 226. The system controller 210 caninterrupt the power relay 218 during a trip condition as a result ofoverheating within the enclosure 200. The system controller 210 will notclose the power relay 218 until the enclosure temperature drops below aconfigurable limit for a predetermined time period. In one embodiment,the predetermined time period is four minutes. This time period isdetermined to be a good compromise between proper cooling time of theenclosure, lighting fixture, and lighting fixture lamp and the minimumamount of time required for certain types of lighting fixture lamps tore-ignite after being deactivated. Certain types of lamps are unable toimmediately reactivate because of greatly increased voltage demands ofhot lighting fixture lamps.

The system controller 210 sends heater duty cycle data to the HDC 220.The HDC enables at least one heater 228 to heat the air within theenclosure 200 in order to maintain the relative humidity of the internalair volume below the minimum value.

FIG. 3 is a graph that illustrates relative humidity values with respectto internal air temperature values as may be used by various embodimentsof the present disclosure. For the sake of clarity, acronyms anddefinitions for various operational parameters and programmed settingsare set forth below. The terms listed and the definitions provided areexemplary only. It will be appreciated that actual parameters andsettings utilized during operation of the enclosure 300 can vary withinthe scope of the claimed subject matter.

Fan Duty Cycle Controller (FDC) 118: A system to switch the fan power onperiodically according to the required duty cycle relayed by the fantemperature control sub-system.

Heater Duty Cycle Controller (HDC) 120: A system to control the duty ofthe heaters, according to the required duty cycle determined by theheater temperature control sub-system.

Minimum Temperature Tracking (MTT) 110: A system to determine theminimum or ideal temperature that will be required to keep the relativehumidity of the enclosure internal environment within the requirement ofthe maximum allowed relative humidity and the minimum enclosure internaltemperature.

Heater Temperature Control sub-system (HTC) 114: A system to maintain aminimum temperature as determined by the ideal temperature.

Fan Temperature Control sub-system (FTC) 112: A system to cool theenclosure proportionately when the enclosed temperature rises above thecooling threshold.

Load Power (PWR) 116: Real-time load power calculation. Fan_Duty_Factor:The parameter from which the FDC determines operation duration andfrequency of the fan(s).

Heater_Duty_Factor: The parameter from which the HDC determinesoperation duration and frequency of the heater(s).

Max_Humidity 320: The maximum configurable target of the internalhumidity control, independent of internal air temperature.

Upper_Temp 312: The maximum target of the internal temperature control,independent of internal air relative humidity.

Lower_Temp 318: The minimum configurable target of the internaltemperature control, independent of internal relative humidity.

Minimum_Temp: The calculated minimum target of the internal temperaturecontrol required to maintain a relative humidity at or belowMax_Humidity.

Limit_Temp 310: The temperature at which the trip condition is engaged.Ideal_Temp 316: The temperature which causes the maximum allowablerelative humidity.

Target_Temp 314: The temperature between Ideal_Temp 316 and Upper_Temp312 that the system adjusts to maintain.

Standard Operating Condition: The state in which the enclosure 100 ispowered and turned on.

Digital Enclosure Control Operating System (DECOS): maintain theenvironment within an enclosure in an optimal way that meets the electedlimits determined by the operational criteria.

To maintain the temperature in the enclosure 300, the system utilizesdifferent system duty factor functions to determine temperature targetsin real-time. The Limit_Temp 310 is a user-defined temperature enables atrip condition which disables power to the lighting fixture. In oneembodiment, the Limit_Temp 310 should be set above normal operatingtemperatures, but below a temperature where equipment damage couldoccur. The Upper_Temp 312 is a user-defined temperature that is themaximum target of the internal temperature control. The system willadjust the fan duty cycle to keep the temperature of the volume of airwithin the enclosure 300 below the Upper_Temp 312. The fan duty cyclewill enable the cooling fans in the temperature range 302 toward theTarget_Temp 314. The Ideal_Temp 316 is the minimum temperature at whichthe user-defined Max_Humidity 320 target is reached. The system willadjust the heater duty cycle to keep the temperature of the volume ofair within the enclosure 300 above the Ideal_Temp 316. The heater dutycycle will enable the heaters in the temperature range 304 toward theTarget_Temp 314.

The Target_Temp 314 is a temperature above the Ideal_Temp 316 and belowthe Upper_Temp 312 at which the system will maintain the temperature ofthe volume of air within the enclosure 300 according to the duty cyclefunctions. The Target_Temp 314 is shown as the temperature range 306.The Target_Temp 314 will adjust to different parameters of the system.In one embodiment, the Target_Temp 314 will adjust toward the Ideal_Temp316 if the lighting fixture is not powered. This adjustment will lowerthe duty cycle of the fans and cause the least amount of power drawwhile emitting the least amount of noise. In another embodiment, theTarget_Temp 314 will adjust toward the Upper_Temp 312 when the lightingfixture is powered. This adjustment will lower the duty cycle of thefans and emit the least amount of noise.

The above sub-systems and parameters are exemplary only. In othercontemplated embodiments, more or fewer sub-systems may be utilized inthe enclosure environment control system. Moreover, the values and datastored therein may also vary.

The principles, representative embodiments, and modes of operation ofthe present disclosure have been described in the foregoing description.However, aspects of the present disclosure which are intended to beprotected are not to be construed as limited to the particularembodiments disclosed. Further, the embodiments described herein are tobe regarded as illustrative rather than restrictive. It will beappreciated that variations and changes may be made by others, andequivalents employed, without departing from the spirit of the presentdisclosure. Accordingly, it is expressly intended that all suchvariations, changes, and equivalents fall within the spirit and scope ofthe claimed subject matter.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. An enclosure comprising:(a) an at least one fan configured to exchange internal air withexternal air; (b) an at least one heater configured to raise internalair temperature; (c) a system controller configured to: (i) cause the atleast one fan to operate when an internal air temperature measurementmeets a predetermined temperature criteria; and (ii) cause the at leastone heater to operate when a relative humidity measurement of theinternal air meets a predetermined humidity criteria.
 2. The system ofclaim 1, wherein the enclosure includes a power relay that is configuredto interrupt power to a lighting fixture housed within the enclosure. 3.The system of claim 2, wherein the power relay may be switched remotely.4. The system of claim 1, wherein the system controller includes remotedata communication.
 5. The system of claim 1, further comprising an atleast one fan configured to promote mixture of the air inside theenclosure.
 6. The system of claim 1, wherein the system controllercauses the at least one fan to operate based on a calculated fan dutycycle and the at least one heater to operate based on a calculatedheater duty cycle.
 7. A method of controlling the internal environmentof an enclosure, the method comprising: (a) setting a relative humidityvalue to a configurable limit during a standard operating condition; (b)setting a temperature value to a configurable limit during a standardoperating condition; (c) monitoring the temperature and relativehumidity within the enclosure; (d) in response to determining that achange in temperature is required: (i) calculating the required dutycycle of an at least one heater and causing it to operate to maintainrelative humidity below the configurable limit; and (ii) calculating therequired duty cycle of an at least one fan and causing it to operate tomaintain temperature below the configurable limit.
 8. The method ofclaim 7, wherein a system controller selectively engages a tripcondition in response to temperature, the temperature exceeding theconfigurable limit during operation, wherein the system power istemporarily unavailable until after the temperature has dropped belowthe configurable limit for a predetermined time.
 9. The method of claim8, wherein the predetermined time is 4 minutes.
 10. The method of claim7, wherein a lighting fixture input power value is monitored to notexceed the rated limit of the enclosure and alter the required dutycycle of the at least one heater.
 11. The method of claim 7, wherein theduty cycle of the fan in minimized to emit the least amount of noise.12. The method of claim 7, further comprising an at least one fanconfigured to stir the air inside the enclosure for increased accuracyof temperature monitoring.
 13. A method of controlling the internalenvironment of an enclosure, the method comprising: (a) receiving a setof sensor values from a plurality of sensors; (b) executing more thanone system duty factor function based on the set of sensor values togenerate a fan duty factor and a heater duty factor associated withsystem duty factor function; (c) causing a fan duty control and a heaterduty control to operate an at least one fan and an at least one heateraccording to the fan duty factor and heater duty factor, respectively.14. The method of claim 13, wherein the more than one system duty factorfunction compares an internal air temperature value to a configurableupper temperature limit.
 15. The method of claim 13, wherein the morethan one system duty factor function compares an internal airtemperature value to a minimum temperature tracking system idealtemperature, the ideal temperature calculated to maintain a configurableinternal air relative humidity limit.
 16. The method of claim 15,wherein the minimum temperature tracking system ideal temperature iscalculated based on an internal air temperature measurement and aninternal air relative humidity measurement.
 17. The method of claim 13,wherein the plurality of sensors include: a temperature sensor, arelative humidity sensor, a voltage sensor, and an amperage sensor. 18.The method of claim 17, wherein the more than one system duty factorfunction compares the voltage sensor reading and the amperage sensorreading to determine a plurality of electrical load power ranges. 19.The method of claim 18, wherein one of the electrical load power rangessignifies that an enclosed lighting fixture is powered, but an enclosedlighting fixture lamp is not active; a separate electrical load powerrange signifying that the enclosed lighting fixture is powered and theenclosed lighting fixture lamp is active.
 20. The method of claim 19,wherein a system controller records the duration the enclosed lightingfixture lamp is active.